The introduction of new techniques in perinatal care and the formation of regionalized perinatal care programs have been credited for most of the decline in perinatal mortality in the U.S. since the mid 1960s. Nevertheless, when examined at the community level rather than at the individual neonatal intensive care unit level, evidence of effectiveness is mixed. This study proposes to evaluate a perinatal cooperative among 15 hospitals in Southern New Jersey. First, perinatal, neonatal and infant mortality rates and low birth weight rates are studied in Southern New Jersey and a comparison area in New Jersey between 1975 and 1985. This period includes years before, during and after the implementation of the Cooperative. Vital records are the source of data from which trends in mortality and low birth weight are studied in relation to implementation of the Cooperative, changing characteristics of the childbearing population, changing use of prenatal care and changing birth weight specific mortality. Secondly, the appropriateness and the outcomes of transfer for high-risk neonates and pregnant women is evaluated. A stratified random sample of approximately 3500 births will be selected from community hospitals for each of two periods of time 1975 - 1977 (before) and July 1982 to June 1985, after implementation of the Cooperative. Compairsons will be made between transferred and non-transferred neonates, neonates transferred from community hospitals and those born at the perinatal center and subsequently admitted to the neonatal intensive care unit, and neonates transferred after birth and those transferred antenatally. Diagnosis of transfer and the severity of neonatal morbidity will be studied. Outcomes are length of hospital stay and neonatal mortality. In addition, pregnant women transferred to the perinatal center during July 1982 and June 1985 will be compared to pregnant women with similar diagnosis and intrapartum risk, kept at the community hospitals. Outcomes are: type of delivery, maternal fever, length of maternal hospital stay, neonatal morbidity, neonatal length of hospital stay and neonatal mortality.